Grandmaster Fabiano Caruana combined extraordinary opening preparation
with accurate calculation to win his second consecutive game at the 2014
Sinquefield Cup, leaving the rest of the highest-rated field in history
snapping at his heels.

In round two, Caruana may have been surprised by Vachier-Lagrave's Caro-Kann Defense, though he used the chance to employ some preparation done with his second, Vladimir Chuchelov, a few months ago -- readying for a game against Azeri GM Shakhriyar Mamedyarov.

With 5...c5 and 6...Qb6, Vachier-Lagrave ventured into a super-sharp line of the Short Variation, but Caruana's 15.g4!?, followed by the equally remarkable 17.Rf2!, was new and unexpected. Vachier-Lagrave began burning time, falling an hour behind on the clock, though his reaction was adequate -- until 17...Nh6. Now Caruana was on his own, spending 13 minutes calculating through complications to find the only winning response: 18.Bd3!

The rest of the game was pure suffering for Vachier-Lagrave, short of time and presented with a variety of losing options. The Frenchman continued, despite being down a piece, but after 30 moves he had nothing for the lost material and resigned.

The game of the day was expected to be GM Hikaru Nakamura's attempt to secure his first career victory against GM Magnus Carlsen. Nakamura had gone close to knocking over the World Champion with the White pieces twice already in 2014, but Carlsen had turned the tables and won both times.

Nakamura's Spanish Opening was met by the surprising 3...g6 -- a move which Nakamura himself had used to beat then-World Champion Viswanathan Anand in 2013. The American reacted along classical lines, leading the game into positions resembling a King's Indian Defence, though without a key pair of bishops.

US #1 Hikaru Nakamura vs. World Champion Magnus Carlsen

Carlsen surprised both Nakamura and the commentators with the unusual idea 14...c6, playing on the side of the board where Nakamura was attacking. Nakamura's reaction led to a roughly equal position before Carlsen lashed out with 18...Nh5!!?, sacrificing one and possibly two pawns.

With 21.f6 and 24.Qb1! -- a move Carlsen had missed -- Nakamura maintained the balance, and soon the World Champion was forced to sacrifice a bishop to achieve perpetual check.

The result was reasonably satisfactory for both players: Carlsen has survived his first two games with the Black pieces and will benefit with the first move in five of his next eight games, while Nakamura has safely negotiated games against the tournament's two highest-rated players.

GM Levon Aronian briefly regained his world number two ranking -- briefly being for about two minutes, until Caruana earned his second victory -- after winning a game against GM Veselin Topalov that looked almost hopeless for the Armenian after just 15 moves.

Playing White, Aronian faced Topalov's Slav with a well-known plan, but 9...Ne4!? sent him into a death spiral. The World No. 2 had spent only seven minutes before playing into a forced sequence, a series that ended with Aronian staring at 14...Bxd4! in disgust.

Aronian found a way to play on, sacrificing the exchange, and Topalov continued to allow counterplay. After black’s disastrous decision to castle queenside (instead of kingside), Aronian believed that he was close to winning, pointing out the cute variation 23...Kb7 24.Bxc6+! Kxc6 25.Qg2+ with a decisive attack.

Aronian admitted luck after he demonstrated the game to a crowd in the World Chess Hall of Fame but, lucky or not, the Armenian has moved into second place in the tournament, half a point behind Caruana. Topalov, meanwhile, is languishing on 0/2, blaming calculation errors for ruining decent positions against both Caruana and Aronian.
Follow along daily rounds featuring commentary by GMs Yasser Seirawan, Maurice Ashley and CLO editor WGM Jen Shahade starting at 1:50 CST/2:50 EST on uschesschamps.com/live